Connecting rod



March 1, 1932. p. E. ANDERSON CONNECTING ROD Filed Oct. 13, 1930hI/IIIIlI/A INVENTOR Par/J 74/74 16 ram ATTORNEYS R H Q Patented Mar. 1,1932 UNITED STATES DAVID E. ANDERSON, or DETROIT, MICHIGAN, AssIGNoR To'RCHN ALUMINUM ANn BRASS CORPORATION, or DETROIT, MICHIGAN, ACORPORATION or MICHIGAN CONNECTING ROD Application filed October 13,1930. Serial No. 488,494.

This invention relates to connecting rods designed for use in high speedinternal combustion engines and consists in the novel construction ashereinafter set forth.

In the drawings:

Figure 1 is a side elevation partly in section of my improved connectingrod;

Figure 2 is a central longitudinal section therethrough Figure 3 is abottom plan view of the cap.

In the present state of the art all manufaoturers of high speed internalcombustion engines are experiencing a short life from connecting rodbearings. This is primarily due to the fact that bearing loads increaseasthe square of the speed with the result that heat frictionallygenerated frequently rises to the point where the Babbitt lining ismelted. To overcome this difliculty connecting rods have been made ofaluminum which has a much higher thermal conductivity than steel. Thesehave not, however, proven satisfactory, chiefly through the highcoefficient of expansion of the aluminum which renders it difiicult tohold the bearing tight at high temperatures without having it too tightat low temperatures.

The present invention is based on the discovery that the frictional heatof the hearing may be more'rapidly and successfully dissipated throughthe cap than through the body of the rod. The reason for this is that athigh speed operation the bearing in the cap of the rod is more heavilyloaded than the bearing in the body. This in turn is due to the factthat at high speed operation the inertia forces are far in excess of theexplosion forces as the resultant load from explosion, compression,inertia and centrifugal force falls to a great extent on the cap. Thisbeing the case, more heat will be frictionally developed in the cap thanin the rod.

My improvement consists essentially in a construction of rod, the bodyportion of a which is formed of steel, and the cap of aluminum alloy.The steel body being of the same material as the crank pin will have acorresponding rate of expansion and by properly designing this steelbody, the expansion of the-aluminum cap may be held Within perpate thesame.

consequent higher convection rate through contact with the air.

In detail, A is a connecting rod preferably formed of a steel forgingand having the head B forming a half bearing for the crank pin. C is acap formed of aluminum, magnesium or other light materials having a highrate of thermal conductivity. This cap is designed with projectingsegmental fins D for increasing both the extent of radiating surface andalso the strength and rigidity of the structure. Both cap and body ofthe rod are provided with Babbitt linings E E. The cap is secured bybolts F and clamping nuts G.

The construction as above described has been subjected to severe testsof running continuously at a high rate of speed without detrimentalresults. This is due to the fact as above set forth that the heat isdirectly and effectively dissipated from the point of generation. Alsoconsiderable weight is saved by making the cap of aluminum in place ofone of steel.

What I claim as my invention is:

1. A connecting rod comprising a body portion formed of steel and a capfor the crank pin end of the rod formed of a metal having a much highercoefficient of thermal conductivity fashioned to dissipate the heat fromthe bearing.

2. A connecting rod comprising a body formed of steel and a cap for thecrankpin end of the rod formed of a metal of the aluminum groupfashioned to dissipate the heat from the bearing.

3. A connecting rod comprising abody including a half bearing for thecrank pin the said body and half bearing being formed of steel, and acap formed of an alloy chiefly of metal of the aluminum group fashionedto dissipate the heat from the bearing.

4. A connecting rod comprising a body infor the crank pin aring beingformed steel, a complementary cap formed of an oup and having a Babbittlining said cap eing fashioned to dissipate the heat fromthe bear- Intestimony whereof I affix my signature.

DAVID E. ANDERSON.

